P.challengeri is a brown sea cucumber with white spots, green tentacles and yellow tube feet. It is a medium-sized species, trapezoidal in section and tapering towards the ends. The body is rigid and rough with numerous white calcareousprotuberances. Spicules are small nodular buttons, baskets and large plates (P. challengeri spicules). It is a coastalspecies, dredged in 15-60 m.